21130818186878 has 16 divisors (see below), whose sum is σ = 31704037714944. Its totient is φ = 10562805876600.

The previous prime is 21130818186869. The next prime is 21130818186883. The reversal of 21130818186878 is 87868181803112.

It is a super-2 number, since 2×21130818186878² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21130818186878.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 196784903 + ... + 196892253.

It is an arithmetic number, because the mean of its divisors is an integer number (1981502357184).

Almost surely, 2^{21130818186878} is an apocalyptic number.

21130818186878 is a deficient number, since it is larger than the sum of its proper divisors (10573219528066).

21130818186878 is a wasteful number, since it uses less digits than its factorization.

21130818186878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130687.

The product of its (nonzero) digits is 8257536, while the sum is 62.

The spelling of 21130818186878 in words is "twenty-one trillion, one hundred thirty billion, eight hundred eighteen million, one hundred eighty-six thousand, eight hundred seventy-eight".